diff --git a/esphome/components/nrf52/framework.py b/esphome/components/nrf52/framework.py
index fa6f7d57ade..623cd4eef3d 100644
--- a/esphome/components/nrf52/framework.py
+++ b/esphome/components/nrf52/framework.py
@@ -133,7 +133,15 @@ def get_build_env() -> dict:
     env = os.environ.copy()
     env["PATH"] = str(venv_bin_dir) + os.pathsep + env.get("PATH", "")
     env["ZEPHYR_BASE"] = str(_get_framework_path(version) / "zephyr")
-    env["Zephyr-sdk_DIR"] = str(_get_toolchain_path(TOOLCHAIN_VERSION) / "cmake")
+    # ZEPHYR_SDK_INSTALL_DIR is the variable Zephyr documents for pointing at
+    # the SDK: FindZephyr-sdk.cmake reads it (from the environment, via
+    # zephyr_get) and passes it straight to find_package as a HINT. This
+    # matters because the SDK lives in the esphome cache dir, which is not on
+    # the module's static search path (/usr, /opt, $HOME, ...). A generic
+    # "Zephyr-sdk_DIR" environment hint proved unreliable here: containerized
+    # non-root builds failed to locate the SDK with it, while
+    # ZEPHYR_SDK_INSTALL_DIR fixed the same invocation.
+    env["ZEPHYR_SDK_INSTALL_DIR"] = str(_get_toolchain_path(TOOLCHAIN_VERSION))
     return env
 
 
diff --git a/tests/unit_tests/test_nrf52_framework.py b/tests/unit_tests/test_nrf52_framework.py
index bb5bc8c064c..830e9efba52 100644
--- a/tests/unit_tests/test_nrf52_framework.py
+++ b/tests/unit_tests/test_nrf52_framework.py
@@ -1,6 +1,7 @@
 """Tests for esphome.components.nrf52.framework helpers."""
 
 import hashlib
+import os
 from pathlib import Path
 from types import SimpleNamespace
 from unittest.mock import patch
@@ -12,11 +13,13 @@ from esphome.components.nrf52.framework import (
     TOOLCHAIN_VERSION,
     _get_toolchain_platform_info,
     check_and_install,
+    get_build_env,
     get_sdk_nrf_tools_path,
 )
 from esphome.config_validation import Version
 from esphome.const import KEY_CORE, KEY_FRAMEWORK_VERSION
 from esphome.core import CORE, EsphomeError
+from esphome.framework_helpers import get_python_env_executable_path
 
 
 @pytest.fixture(autouse=True)
@@ -252,6 +255,42 @@ class TestCheckAndInstall:
         assert substitutions["extension"] == "tar.xz"
 
 
+# ---------------------------------------------------------------------------
+# get_build_env tests
+# ---------------------------------------------------------------------------
+
+
+def test_get_build_env(
+    nrf52_dirs: SimpleNamespace, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """get_build_env exposes ZEPHYR_SDK_INSTALL_DIR pointing at the toolchain root.
+
+    ZEPHYR_SDK_INSTALL_DIR is the variable Zephyr's FindZephyr-sdk.cmake
+    explicitly consumes (from the environment) and uses as a find_package
+    HINT. The old Zephyr-sdk_DIR environment hint proved unreliable in
+    containerized non-root builds and was removed.
+    """
+    monkeypatch.setenv("SOME_PREEXISTING_VAR", "kept")
+
+    env = get_build_env()
+
+    tools = get_sdk_nrf_tools_path()
+    venv_bin_dir = get_python_env_executable_path(
+        tools / "penvs" / f"v{_TEST_SDK_VERSION}", "python"
+    ).parent
+    assert env["PATH"].startswith(str(venv_bin_dir) + os.pathsep)
+    assert env["ZEPHYR_BASE"] == str(
+        tools / "frameworks" / f"v{_TEST_SDK_VERSION}" / "zephyr"
+    )
+    # Toolchain root, not the cmake/ subdir
+    assert env["ZEPHYR_SDK_INSTALL_DIR"] == str(
+        tools / "toolchains" / TOOLCHAIN_VERSION
+    )
+    assert "Zephyr-sdk_DIR" not in env
+    # The rest of the process environment is inherited
+    assert env["SOME_PREEXISTING_VAR"] == "kept"
+
+
 # ---------------------------------------------------------------------------
 # get_sdk_nrf_tools_path tests
 # ---------------------------------------------------------------------------